Well, I did not turn on a monster (256 MB RAM), and I have no worries, they pile up without any problems ... No noticeable bugs.
I use the classic series in recent months, and these are my plugs for main effects. I find high quality, super easy to use system (pots), use very little CPU and then they are free too ... So the report qual / price is exceptional. I have not tried many other plugs on my machine (mostly freeware and demos), and their classic series is much higher. To be tested on other systems plugs effect significantly more expensive, I prefer the simplicity and usability effects Kjaerhus. Missing more than a distortion in the series and it will be perfect.